I have a driveline question that I have found little or no help with anywhere. I have an 87 Firebird that has the V6 and is bone stock. I was wondering how I can make it go faster . I was looking at a lower ratio rear end with a posi differential, say, with a ratio down in the lower 3s or upper 2's, but my understanding is that i need more torque to begin to drive one properly. I know that a auto tranny shift kit is going to be needed when I can do it properly, and I am really not sure of what rear end ratio I have now, but I know I need a lower ratio to get more speed. I have barely any knowledge of this area and will soak up any information I can get.

 

You will not "get more speed" by using a lower numerical ratio. You'll just make the car slower, by making it harder for the engine to get it moving. Attack the problem at it source. All else is futile.

 

Yes I know, but after I increase the HP and torque with some engine upgrades, wouldn't I still end up going to a lower ratio rear end to go faster? I mean 85 MPH sucks. I can get away doing 72-75 on route 90 here, and I'm looking to put in a decent run at the strip sometime in the future, maybe after I drop in a V8 or somethng. And as for right now, I don't really care about that pin-you-to-the-back-of-your-seat acceleration, I just want top end speed, something that will be used better when I drop in that V8 I've been wanting...

 

When you get an engine with some top-end horsepower into there, you'll find that you won't have a "top speed" problem any more.

Right now your problem is that the engine's HP output is equal to the car's requirement at some speed, say 85 mph, so it won't go any faster than that no matter what gear is in it. A motor with more HP will push the car faster before it reaches the speed at which the rolling power requirement is equal to the engine's output.